Name: Melanie Schroers
Title: Impacts and Synoptic Patterns of Subseasonal to Seasonal Extreme Precipitation Events in the United States
Location: NWC 1350
Time: 3:00 PM
Series: Weather and Climate Systems
Abstract: Extreme precipitation can cause devastating impacts to many sectors of society and the economy, including water management, infrastructure, public health and transportation. In order to better prepare for these risks, further work is needed to understand extreme precipitation events that occur at the subseasonal to seasonal timescales (S2S event). For example, in May 2015, Oklahoma and Texas received up to 20+ inches of rain throughout the month that resulted in widespread flooding and mandatory evacuations. Extreme precipitation events lasting 14-days were found for seven regions across the continental U.S. for the time period of 1981 to 2018 using Parameter Elevation Regression on Independent Slopes Model (PRISM) daily precipitation data. S2S events are determined based on a set of criteria including: percentile thresholds, areal extent, and temporal distribution of precipitation. This work identifies impacts related to these events using NOAAâ€™s storm event database, as
well as the associated atmospheric conditions. These events are associated with a higher number of floods, flash floods, high wind reports and in some regions heavy-snow or tropical storms when compared to random 14-day periods, further highlighting the importance of these extended wet periods. Principal component analysis is performed for each regionâ€™s 500hPa height fields from reanalysis during the S2S event. Investigation of how often these patterns occur during the events as well as during non-events will give a first look into predictability. Improving the prediction of these S2S events will help mitigate impacts for our stakeholders.